Various capacitive probe measurement apparatuses have already been proposed, for example in the following documents: FR-A-2 234 555, FR-A-2 402 193, FR-A-2 451 024, FR-A-2 500 169, and FR-A-2 500 337.
Compared with conventional systems having a float and a resistive strip, capacitive probe measurement apparatuses have the particular advantage of having no moving parts. However, in spite of this manifest advantage, capacitive measurement apparatuses are little used at present because they do not give full satisfaction, in particular with respect to accuracy.
The main object of the present invention is to provide a novel capacitive probe measurement apparatus having improved accuracy over prior systems.
An auxiliary object of the present invention is to provide a capacitive probe measurement apparatus compatible with all types of fuel, in particular with oxygen-containing fuels having a high content of methanol or of ethanol.
Another auxiliary object of the present invention is to provide capacitive probe measurement apparatus having high sensitivity, i.e. providing a large change in capacitance over the full range of measurement.